What is itch?
Itch (pruritus) is a symptom that can be caused by a large number of conditions. For example, skin disorders such as eczema and illnesses such as jaundice can cause a generalised itch. Itch of the anus (pruritus ani) and itch of the vulva (pruritus vulvae) are common and have various causes. See separate leaflets called ‘Pruritus Ani (Itchy Bottom)’ and ‘Pruritus Vulvae (Itchy Vulva)’ for details. However, in many cases no cause is found for an itch. This article deals only with itch that is not due to any underlying skin or medical condition. This is called itch of unknown cause.
If no cause for an itch is obvious, then your doctor may advise that you have some tests to see if there is an underlying cause for the itch. However, in many cases, the tests are normal and the cause remains a mystery.
Itching can occur over your entire body or just in one area. It can be very unpleasant and uncomfortable.
One possible factor is that in some people with itch of unknown cause, their skin may be drier than average, which may contribute to the itch. Itch of unknown cause is most common in older people whose skin tends to be drier than younger people. Itch tends to be worse at night and may be made worse by bathing. Any part of the skin may be affected.
What are the treatments for itch of unknown cause?
The following may help to improve your itching:
- Keep your nails short to limit any damage done to your skin by scratching. As much as possible try not to scratch. It is thought that scratching can make itch worse and an ‘itch-scratch’ vicious cycle may develop with regular scratching. (That is, you itch more because you scratch, so you scratch more because you itch more … and so on.)
- Keep cool as much as possible. Some people find having cool (or lukewarm) baths or showers soothing.
- Avoid irritants such as soaps, bubble bath, detergents and any other things that seem to irritate. For example, woollen clothes. Cotton clothes are usually preferable.
- Steroid creams. Hydrocortisone cream can be bought over-the-counter and can sometimes help on small areas of itchy skin. Alternatively, your doctor may prescribe you a steroid cream. However, these should only be used in very small amounts and for as short a time as possible.
- Dry skin may be making the itch worse. Moisturisers (emollients) are useful to keep the skin supple and moist. They can be applied once a day or several times a day if your skin becomes very dry. Water and soap dry out the skin as they wash away the natural skin oils. Therefore, the most important time to use moisturisers is after a bath or shower. Moisturisers work by providing a replacement for these body oils and keeping the skin moist. Numerous moisturisers are available as creams, ointments, bath/shower additives and also to use instead of soap. It may be worth trying out a few to see which is the most suitable. These can be bought over-the-counter or different ones are available on prescription from your doctor.
- Antihistamine medication is sometimes tried. Antihistamines are useful for some skin conditions that cause itch such as urticaria. A trial of medication may be worth a try. However, they do not help with all types of itch. For itch of ‘unknown cause’ they may have little effect. Some antihistamines also tend to make you drowsy. However, these types of antihistamines may be worth trying at bedtime if itch is troublesome at night. Your doctor or pharmacist can advise you further.
- Relaxation techniques can be beneficial for some people.
The amount of discomfort from itch can vary from person to person and from time to time in the same person. A referral to a skin specialist may be advised if your itching persists or is severe. There are different treatments which are being investigated in clinical trials which may be available in the future.